1. Field of the Invention
The present invention relates to an image display device and a manufacturing method therefor.
2. Description of the Related Art
Generally, for example, an image display device including a flexible resin substrate is more light in weight and has excellent impact resistance and flexibility compared with an image display device including a glass substrate.
In a case where such an image display device is, for example, a liquid crystal display device, the image display device includes a pair of substrates sandwiching liquid crystal therebetween, and each of the substrates is formed of a resin substrate. In this case, on a surface of one resin substrate on the liquid crystal side, a conductive film, a semiconductor film, an insulating film, and the like which are patterned are laminated in a predetermined order, to thereby form a laminate including a gate signal line, a drain signal line, a thin-film transistor, a pixel electrode, and the like. Note that, in this specification, in some cases, the laminate is referred to as thin-film transistor (TFT) circuit layer.
Further, as for the liquid crystal display device having such a structure, there is known a type in which a buffer layer is formed between the resin substrate and the TFT circuit layer. In a case where the liquid crystal display device (image display device) is formed by a transfer method in which a glass substrate is first used as a temporary substrate, the buffer layer has been used so as to prevent impurities in the glass substrate from penetrating into the TFT circuit layer. Further, in a case where the liquid crystal display device (image display device) is formed by a direct formation method in which the TFT circuit layer is formed directly on the resin substrate, the buffer layer has been used so as to enhance adhesion between the resin substrate and a metal layer (for example, gate signal line) which is the lowermost layer of the TFT circuit layer. For example, a dense film such as a silicon nitride film may be used as the buffer layer (JP 2005-254541 A).